TuesdaySeptember 26,2017

The first Megamouth Shark fossil to be found in Asia has been unearthed in Okinawa

The fossilized megamouth shark tooth, which is about 1 centimeter long.

January 21, 2014 Ryukyu Shimpo

Okinawan researchers have unearthed the fossilized tooth of a megamouth shark on the east coast of the southern island prefecture. There are few fossil specimens of the shark worldwide. Fossilized remains of the shark had only been found in North America and Europe previously. It is the first time a fossilized tooth from a megamouth shark has been found in Asia.

Kiyoko Yokoyam of the Okinawa Churashima Foundation unearthed the fossilized tooth. She and Taketeru Tomita, a researcher at the foundation’s Comprehensive Research Center, will co-write a thesis on the finding. It will appear in Paleontological Research, an English academic journal of the Palaeontological Society of Japan, this spring. Tomita who specializes in shark palaeontology, said, “The finding has revealed that megamouth sharks existed all around the world. I hope our study makes a major contribution to understanding the evolution of the shark.”

A liquid specimen from a rare five-meter-long megamouth shark . At the Churaumi Plaza of the Okinawa Churaumi Aquarium in Motobu, Okinawa.

The fossilized megamouth shark tooth found in Okinawa is about 1 centimeter long and hook-shaped. According to Tomita, the tooth is believed to be between 3 million and 10 million years old because the geological formation of the coast where the fossil was found, belongs to the Neogene.

Nine-year-old Honoka Iwase played a part in Yokoyama’s discovery of the tooth. Iwase introduced Yokoyama to the east coast of Okinawa, where many fossil remains have been found. Yokoyama started to excavate the area and found the fossilized megamouth shark tooth.

Yokoyama said, “When I found the tooth, I did not realize that it was a rare finding. The meeting with Iwase and Tomita led to this finding and an official record of the fossilized megamouth shark tooth in Asia.”

Glossary: Megamouth Shark
Megamouth sharks were first discovered in Hawaii in 1976. They feed on plankton and can grow to about 5 to 6 meters in size. Only about 60 of them have been found or captured worldwide. Much of their nature remains unknown and they are called “the phantom shark.” It is rare to see a living Megamouth shark. Findings of its fossilized remains are rarely reported. Fossilized remains of the shark’s teeth have been found in 10 regions of North America and Europe. There is no case of public institutions in Asia owning the shark’s fossil remains or publishing theses on the shark in the past.